No joke: In the Bible, the term “salvation” doesn’t mean what most western Christians imagine it means.
It’s a Hebrew concept of being rescued, redeemed, pulled out of a bad situation. It meant that with most pagans, including those who spoke Greek. The western concept is derived from the Roman idea of justification before a magistrate. Note that this is not what the Apostles meant by “justification” either. They were referring to a common image based on a very personal form of feudal justice.
To be “saved” is not an impersonal judicial arrangement. It is not a status. It means being pulled into God’s personal favor. The concept arises from a world where your “government” was someone who was related to you by blood or covenant. The concept of government in the biblical world excluded strangers.
Granted, invaders could seize the reins of government, but everyone expected that, at the earliest opportunity, the oppressed would throw off the foreign invaders. Even the invaders expected it to come sooner or later. And until it did happen, they would never condescend to get involved in the daily affairs of a subject people. They would exert their control through the organic leadership of the people.
So, you must ditch entirely the image of impersonal law and justice. Being saved means you have made peace with the feudal master, and that feudal master is your relative.
As a theological concept, it refers to standing in God’s favor in this world. It refers to all the promises of covenant life in the here and now. It could imply an eternal destiny, but that’s rarely the first thing you should think of when you read it in the Bible. Thus, it’s more a concept of living in covenant relation with the Lord as a fallen human.
This should remind you that the Calvinist-Arminian debate is nonsense. The Lord offers redemption to people who are not Elect (“all may come”) through the covenant community and what passes for a Christian law code. You aren’t supposed to ask the question of whether this or that person is Elect. You cannot know; it remains a part of the Eternal Realm with all the other ineffable truths. We can talk about how Divine Election works in some contexts, but when it comes to church people doing what they do in Christ, Election is hardly an applicable concept.
All we can say is that, if you can hang in there, you look like the Elect.
What matters is a demonstrated sensitivity to what it means to love each other as Christ loves us. That’s our law code. It is meant to be defined in the context of your daily life, so it will look different in different groups. Do you think Election was a factor in the parable of the Good Samaritan? Nope. What Jesus was saying is that, if someone walks in the Covenant, you must assume they are your brother/sister.
Now, concerning the reference Jesus makes in Matthew 24:23-24, the point He is making is this: We know the Elect have His Spirit. We know that no one else does. People without the Holy Spirit can be fooled more easily by something with spiritual implications. Thus, the issue of false Messiahs is that they would strive to look like the real thing, trying hard to sucker in even the Elect.
Keep in mind the setup here. Satan’s primary mission is to keep us away from the Covenant and its blessings. He profits from stealing our divine inheritance on this earth. He could not possibly gain from keeping us out of Heaven, and is unable to do that in the first place (the Elect are elected by God). He may not even know who the Elect are, so he targets everyone who appears to be walking in the Covenant. A major effort would be to raise up false Christs to mislead.
What Jesus is saying in that passage is that our Enemy is using everything he’s got because he knows only what he can see. It would be really sad if the Elect were pulled off course, because then everyone else will be, too.